High-Precision Alignment for Low Temperature Wafer Bonding
High-Precision Alignment for Low Temperature Wafer Bonding
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DOI：
10.1149/1.2982909
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发表时间：
2008-08
期刊：
影响因子：
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通讯作者：
Chenxi Wang;S. Taniyama;Yinghui Wang;T. Suga
中科院分区：
文献类型：
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作者：
Chenxi Wang;S. Taniyama;Yinghui Wang;T. Suga
提出了一种基于中心对称莫尔光栅的晶圆间对准方法。由两个中心对称的方形光栅产生的莫尔条纹对失调和失调方向高度敏感，而不需要任何外部参考。利用两对叠栅光栅，在晶片尺度上同时测量了键合晶片在XY-θ方向上的失调。在我们的实验中，在XY方向上的±0.5 μm数量级的失调可以很容易地识别使用一个简单的红外（IR）显微镜。此外，这些莫尔光栅也适合作为二次对准标记，以实现高精度对准。如果减小中心对称方形光栅的加工误差，莫尔光栅辅助的对准精度可以进一步提高到纳米级。
A novel wafer-to-wafer alignment method is developed using centrosymmetric moiré gratings. Moiré fringes produced by the two centrosymmetric square gratings are highly sensitive with the misalignments and misaligned directions without requiring any external reference. Using two pairs of these moiré square gratings, misalignments of the bonded wafers are determined in XY-θ direction simultaneously on wafer scale. In our experiment, the misalignments in the order of±0.5 μm in XY direction can be easily identified using a simple infrared (IR) microscope. Moreover, these moiré gratings are suitable for being secondary alignment mark to achieve high-precision alignment as well. And the alignment accuracy assisted by these moiré gratings can be further improved to nanometer range if processing errors for the fabrication of the square centrosymmetric gratings are reduced.